The following regression equation was obtained from an analysis with effect coding for four groups with equal n's: y' = XXXXXXXXXX5EI - 2.5E2 - 4.5E3 (a) What is the grand mean of the four...

The following regression equation was obtained from an analysis with effect coding for four groups with equal n's:

y' = 102.5 + 2.5EI - 2.5E2 - 4.5E3

(a) What is the grand mean of the four groups?

(b) What are the means of the four groups, assuming that the fourth group was assigned -1's?

(c) What is the effect of each treatment?